The major objective of this project is to provide both descriptive and interpretive accounts of the complex movements of the mandible in relation to the motor patterns that underlie those movements, during masticatory functioning of normally dentate human subjects. In addition to its importance in biological functioning, the masticatory system is also a unique and experimentally accessible neuromotor model system. Our studies of the human masticatory system rely on simultaneous measurements of the movements of the jaw (in three dimensions) and the actions of all of the jaw elevator muscles. Using computer averaging and cross-correlation techniques, relationships between jaw movements and muscle timing and forcing functions will be quantified. After a data base on normal muscle-movement relationships has been established, our combined electromyographic-magnetometric procedures will be applied to patients with severe malocclusion and temporomandibular joint dysfunctions to determine possible functional bases for these problems, and to pre- and post-operative orthognathic surgery cases for studies of neuromotor compensation and adaptation.